\section{Conclusion and Future Work}
\label{section:conclusion}
In this paper, we presented an empirical case study where we lifted
\gmtoautosar, a transformation that migrates GM legacy models to AUTOSAR, so
that it can be used to transform product lines as opposed to individual
products. 
Lifting required us to adapt the execution engine of DSLTrans, the
model transformation language in which \gmtoautosar is written. We experimented
with the lifted transformation \gmtoautosarlifted, using realistic product lines
of various sizes to study the effect of lifting to the execution time and the
complexity of the resulting product line. 
The observations confirm our theory that lifted model transformations can be
applied to industrial-grade product lines.
However, more optimization is required in order to strike a balance between
keeping the runtime low and avoiding the growth of the size of presence
conditions.
Our experience with lifting \gmtoautosar indicates that
lifting is feasible for transformation languages
like DSLTrans, where individual productions can be lifted while reusing
the engine for matching and scheduling. However, lifting the full range of
language features (not used in \gmtoautosar) requires rethinking 
our lifting method.
In the future, we intend to lift the entire DSLTrans engine, to take into
account its full range of advanced language features such as existential
matching and transitive link matching. We also intend to leverage the experience of
lifting an entire model transformation language to apply our approach to more
complex and powerful transformation languages.

